Functional Analysis Of GATA Transcription Factor PnGATA1in Antarctic Moss Pohlia Nutans

GATA transcription factors play important roles in plant growth, development and response to abiotic stresses. Pohlia nutans was obtained at the24th Antarctic scientific expedition of China. GATA family was picked according to transcriptomical data of P. nutans under cold stress. We cloned them and analyzed their biological functions and mechanisms in our study.In this study, we screened the transcriptomic dataset. And then isolated a GATA transcription factor gene PnGATAl to analyze its biological function.The full length of PnGATAl is867bp.PnGATA1encodes a288amino acids protein with GATA zinc finger domain and is classified into subfamily Ⅱ. The subcellular localization experiment of Arabidopsis protoplasts results indicated that the PnGATA1protein is localized in the cell nucleus. sqRT-PCR analysis showed that PnGATA1genes expression was extraordinary up-regulated in a short time under cold stress, exogenous NAA and ABA hormone treatment. With the gene transformed into yeast, in vivo protein-DNA interactions monitored by yeast one-hybrid assays it revealed that the protein products of PnGATAl gene didn’t has transcriptional activation activity in yeast expression system.Hence PnGATA1was supposed to encode a transcriptional repressor. In order to analyze the functions of PnGATAl, we overexpressed this gene into Arabidopsis columbia-0. It is indicated that, PnGATA1overexpression lines influenced seed germination rate, and inhibited opening rate of cotyledons and the growth of seedlings at germination period in Arabidopsis. Seed germination of PnGATA1overexpression was delayed in containing mannitol, NaCl, ABA MS medium, so transgenic lines under mannitol, ABA, NaCl stress were more sensitive to these stress. In the dark and red light treatment, hypocotyls of overexpression strains were significantly shortened. However under far-red light treatment these hypocotyls were significant elongated. Three-week-old seedings of transgenic Arabidopsis showed smaller and fewer rosette leaf area, shorter petiole, and fewer number of blades. Six-week-old transgenic lines seedlings exhibited shorter and smaller than WT. Overexpression lines had shorter main roots, and showed weakened gravitropisms, and were more sensitive to NPA.qRT-PCR analysis showed that the roots of transgenic Arabidopsis auxin pathway Marker genes AtTIRl,AtMDR, AtMDR4, AtPIN2, AtAUX1,AtPID, AtRCNl expression were significantly up-regulated, AtAXR3had lower expression level.While AtPIN1and AtPIN3didn’t change significantly. By the Laser scanning confocal microscopy, it revealed that the root tips of overexpression lines had abnormal structure. It is remarkable that the cells in columella and lateral root cap were more than WT and they growed in different directions irregularly.In summary, PnGATAl is a transcription factor which plays important roles in growth and development, auxin pathways, light signaling pathways and stress responses in plants.